def test_metrics(self):
f = _segyio.open(self.filename, "r")
binary_header = _segyio.read_binaryheader(f)
ilb = 189
xlb = 193
with self.assertRaises(TypeError):
metrics = _segyio.init_metrics("?", binary_header, ilb, xlb)
with self.assertRaises(TypeError):
metrics = _segyio.init_metrics(f, "?", ilb, xlb)
with self.assertRaises(IndexError):
metrics = _segyio.init_metrics(f, binary_header, ilb + 1, xlb)
metrics = _segyio.init_metrics(f, binary_header, ilb, xlb)
self.assertEqual(metrics['iline_field'], ilb)
self.assertEqual(metrics['xline_field'], xlb)
self.assertEqual(metrics['trace0'], _segyio.textheader_size() + _segyio.binheader_size())
self.assertEqual(metrics['sample_count'], 50)
self.assertEqual(metrics['format'], 1)
self.assertEqual(metrics['trace_bsize'], 200)
self.assertEqual(metrics['sorting'], 2) # inline sorting = 2, crossline sorting = 1
self.assertEqual(metrics['trace_count'], 25)
self.assertEqual(metrics['offset_count'], 1)
self.assertEqual(metrics['iline_count'], 5)
self.assertEqual(metrics['xline_count'], 5)
_segyio.close(f)
with self.assertRaises(IOError):
metrics = _segyio.init_metrics(f, binary_header, ilb, xlb)
def create(filename, spec):
"""Create a new segy file.
Since v1.1
Unstructured file creation since v1.4
Create a new segy file with the geometry and properties given by `spec`.
This enables creating SEGY files from your data. The created file supports
all segyio modes, but has an emphasis on writing. The spec must be
complete, otherwise an exception will be raised. A default, empty spec can
be created with `segyio.spec()`.
Very little data is written to the file, so just calling create is not
sufficient to re-read the file with segyio. Rather, every trace header and
trace must be written to for the file to be considered complete.
Create should be used together with python's `with` statement. This ensure
the data is written. Please refer to the examples.
The `spec` is any object that has the following attributes:
Mandatory:
iline (int/segyio.BinField)
xline (int/segyio.BinField)
samples (array-like of int)
format (int), 1 = IBM float, 5 = IEEE float
Exclusive:
ilines (array-like of int)
xlines (array-like of int)
offsets (array-like of int)
sorting (int/segyio.TraceSortingFormat)
OR
tracecount (int)
Optional:
ext_headers (int)
The `segyio.spec()` function will default offsets and everything in the
mandatory group, except format and samples, and requires the caller to fill
in *all* the fields in either of the exclusive groups.
If any field is missing from the first exclusive group, and the tracecount
is set, the resulting file will be considered unstructured. If the
tracecount is set, and all fields of the first exclusive group are
specified, the file is considered structured and the tracecount is inferred
from the xlines/ilines/offsets. The offsets are defaulted to [1] by
`segyio.spec()`.
Args:
filename (str): Path to file to open.
spec (:obj: `spec`): Structure of the segy file.
Examples:
Create a file::
>>> spec = segyio.spec()
>>> spec.ilines = [1, 2, 3, 4]
>>> spec.xlines = [11, 12, 13]
>>> spec.samples = list(range(50))
>>> spec.sorting = 2
>>> spec.format = 1
>>> with segyio.create(path, spec) as f:
... ## fill the file with data
...
Copy a file, but shorten all traces by 50 samples::
>>> with segyio.open(srcpath) as src:
... spec = segyio.spec()
... spec.sorting = src.sorting
... spec.format = src.format
... spec.samples = src.samples[:len(src.samples) - 50]
... spec.ilines = src.ilines
... spec.xline = src.xlines
... with segyio.create(dstpath, spec) as dst:
... dst.text[0] = src.text[0]
... dst.bin = src.bin
... dst.header = src.header
... dst.trace = src.trace
Copy a file, but shorten all traces by 50 samples (since v1.4)::
>>> with segyio.open(srcpath) as src:
... spec = segyio.tools.metadata(src)
... spec.samples = spec.samples[:len(spec.samples) - 50]
... with segyio.create(dstpath, spec) as dst:
... dst.text[0] = src.text[0]
... dst.bin = src.bin
... dst.header = src.header
... dst.trace = src.trace
:rtype: segyio.SegyFile
"""
f = segyio.SegyFile(filename, "w+")
f._samples = numpy.asarray(spec.samples, dtype=numpy.single)
f._ext_headers = spec.ext_headers if hasattr(spec, 'ext_headers') else 0
f._bsz = _segyio.trace_bsize(len(f.samples))
txt_hdr_sz = _segyio.textheader_size()
bin_hdr_sz = _segyio.binheader_size()
f._tr0 = txt_hdr_sz + bin_hdr_sz + (f.ext_headers * txt_hdr_sz)
f._fmt = int(spec.format)
f._il = int(spec.iline)
f._xl = int(spec.xline)
if not structured(spec):
f._tracecount = spec.tracecount
else:
f._sorting = spec.sorting
f._offsets = numpy.copy(numpy.asarray(spec.offsets, dtype=numpy.intc))
f._tracecount = len(spec.ilines) * len(spec.xlines) * len(spec.offsets)
f._ilines = numpy.copy(numpy.asarray(spec.ilines, dtype=numpy.intc))
f._xlines = numpy.copy(numpy.asarray(spec.xlines, dtype=numpy.intc))
line_metrics = _segyio.init_line_metrics(f.sorting, f.tracecount,
len(f.ilines), len(f.xlines),
len(f.offsets))
f._iline_length = line_metrics['iline_length']
f._iline_stride = line_metrics['iline_stride']
f._xline_length = line_metrics['xline_length']
f._xline_stride = line_metrics['xline_stride']
f.text[0] = default_text_header(f._il, f._xl, segyio.TraceField.offset)
f.bin = {
3213: f.tracecount,
3217: 4000,
3221: len(f.samples),
3225: f.format,
3505: f.ext_headers,
}
return f
def create(filename, spec):
"""Create a new segy file.
Since v1.1
Create a new segy file with the geometry and properties given by `spec`.
This enables creating SEGY files from your data. The created file supports
all segyio modes, but has an emphasis on writing. The spec must be
complete, otherwise an exception will be raised. A default, empty spec can
be created with `segyio.spec()`.
Very little data is written to the file, so just calling create is not
sufficient to re-read the file with segyio. Rather, every trace header and
trace must be written to for the file to be considered complete.
Create should be used together with python's `with` statement. This ensure
the data is written. Please refer to the examples.
Args:
filename (str): Path to file to open.
spec (:obj: `spec`): Structure of the segy file.
Examples:
Create a file::
>>> spec = segyio.spec()
>>> spec.ilines = [1, 2, 3, 4]
>>> spec.xlines = [11, 12, 13]
>>> spec.samples = list(range(50))
>>> spec.sorting = 2
>>> spec.format = 1
>>> with segyio.create(path, spec) as f:
... ## fill the file with data
...
Copy a file, but shorten all traces by 50 samples::
>>> with segyio.open(srcpath) as src:
... spec = segyio.spec()
... spec.sorting = src.sorting
... spec.format = src.format
... spec.samples = src.samples[:len(src.samples) - 50]
... spec.ilines = src.ilines
... spec.xline = src.xlines
... with segyio.create(dstpath, spec) as dst:
... dst.text[0] = src.text[0]
... dst.bin = src.bin
... dst.header = src.header
... dst.trace = src.trace
:rtype: segyio.SegyFile
"""
f = segyio.SegyFile(filename, "w+")
f._samples = numpy.asarray(spec.samples, dtype=numpy.single)
f._ext_headers = spec.ext_headers
f._bsz = _segyio.trace_bsize(len(f.samples))
txt_hdr_sz = _segyio.textheader_size()
bin_hdr_sz = _segyio.binheader_size()
f._tr0 = txt_hdr_sz + bin_hdr_sz + (spec.ext_headers * txt_hdr_sz)
f._sorting = spec.sorting
f._fmt = int(spec.format)
f._offsets = numpy.copy(numpy.asarray(spec.offsets, dtype=numpy.intc))
f._tracecount = len(spec.ilines) * len(spec.xlines) * len(spec.offsets)
f._il = int(spec.iline)
f._ilines = numpy.copy(numpy.asarray(spec.ilines, dtype=numpy.intc))
f._xl = int(spec.xline)
f._xlines = numpy.copy(numpy.asarray(spec.xlines, dtype=numpy.intc))
line_metrics = _segyio.init_line_metrics(f.sorting, f.tracecount,
len(f.ilines), len(f.xlines),
len(f.offsets))
f._iline_length = line_metrics['iline_length']
f._iline_stride = line_metrics['iline_stride']
f._xline_length = line_metrics['xline_length']
f._xline_stride = line_metrics['xline_stride']
f.text[0] = default_text_header(f._il, f._xl, segyio.TraceField.offset)
f.bin = {
3213: f.tracecount,
3217: 4000,
3221: len(f.samples),
3225: f.format,
3505: f.ext_headers,
}
return f
def test_binary_header_size(self):
self.assertEqual(400, _segyio.binheader_size())